Distribution pattern of an expanding Osprey ( Pandion haliaetus) population in a changing environment

We studied the nest site selection and distribution pattern at landscape level of the German Osprey population, and demonstrated how to test the predictions of the ideal free distribution theory and its derivatives on such an expanding population. Information about the location and breeding success of each Osprey nest site between 1995 and 2005 was collected through a long-term monitoring programme. Data of land cover types were acquired from the administrations of each federal state and the CORINE Land Cover database. The results showed that Ospreys preferred landscapes with more water bodies and forests. Such sites were also occupied earlier and had higher local population density. However, in the study period of 11 years, there was a gradual shift from forest-dominated landscapes to agricultural land-dominated landscapes. The breeding success increased over time, with no difference in the breeding success between pairs nesting on trees and poles, whereas there was higher breeding success at nest sites surrounded by more agricultural land and less forest. The more efficient foraging in eutrophic lakes in agricultural landscapes was the most likely cause for the higher breeding success. The distribution pattern of the Ospreys did not match the resource allocation, which deviated from the models tested. We suggested that the proximate cues used for nest site selection mismatched site quality due to anthropogenic environmental changes.     

The essential requirement of an animal heme peroxidase protein during the wing maturation process in Drosophila

Background

Thus far, a handful of genes have been shown to be related to the wing maturation process in insects. A novel heme peroxidase enzyme known as curly suppressor (Cysu)(formerly CG5873), have been characterized in this report because it is involved in wing morphogenesis. Using bioinformatics tools we found that Cysu is remarkably conserved in the genus Drosophila (>95%) as well as in invertebrates (>70%), although its vertebrate orthologs show poor homology. Time-lapse imaging and histochemical analyses have confirmed that the defective wing phenotype of Cysu is not a result of any underlying cellular alterations; instead, its wings fail to expand in mature adults.

Results

The precise requirement of Cysu in wings was established by identifying a bona fide mutant of Cysu from the Bloomington Drosophila Stock Centre collection. Its requirement in the wing has also been shown by RNA knockdown of the gene. Subsequent transgenic rescue of the mutant wing phenotype with the wild-type gene confirmed the phenotype resulting from Cysu mutant. With appropriate GAL4 driver like engrailed-GAL4, the Cysu phenotype was compartmentalized, which raises a strong possibility that Cysu is not localized in the extracellular matrix (ECM); hence, Cysu is not engaged in bonding the dorsal and ventral cuticular layers. Finally, shortened lifespan of the Cysu mutant suggests it is functionally essential for other biological processes as well.

Conclusion

Cysu, a peroxinectin-like gene, is required during the wing maturation process in Drosophila because as a heme peroxidase, Cysu is capable of utilizing H₂O₂, which plays an essential role in post-eclosion wing morphogenesis.

     

Phylogeny of Drosophila and related genera inferred from the nucleotide sequence of the Cu,Zn Sod gene

The phylogeny and taxonomy of the drosophilids have been the subject of extensive investigations. Recently, Grimaldi (1990) has challenged some common conceptions, and several sets of molecular data have provided information not always compatible with other taxonomic knowledge or consistent with each other. We present the coding nucleotide sequence of the Cu,Zn superoxide dismutase gene (Sod) for 15 species, which include the medfly Ceratitis capitata (family Tephritidae), the genera Chymomyza and Zaprionus, and representatives of the subgenera Dorsilopha, Drosophila, Hirtodrosophila, Scaptodrosophila, and Sophophora. Phylogenetic analysis of the Sod sequences indicates that Scaptodrosophila and Chymomyza branched off the main lineage before the major Drosophila radiations. The presence of a second intron in Chymomyza and Scaptodrosophila (as well as in the medfly) confirms the early divergence of these two taxa. This second intron became deleted from the main lineage before the major Drosophila radiations. According to the Sod sequences, Sophophora (including the melanogaster, obscura, saltans, and willistoni species groups) is older than the subgenus Drosophila; a deep branch splits the willistoni and saltans groups from the melanogaster and obscura groups. The genus Zaprionus and the subgenera Dorsilopha and Hirtodrosophila appear as branches of a prolific “bush” that also embraces the numerous species of the subgenus Drosophila. The Sod results corroborate in many, but not all, respects Throckmorton's (King, R.C. (ed) Handbook of Genetics. Plenum Press, New York, pp. 421–469, 1975) phylogeny; are inconsistent in some important ways with Grimaldi's (Bull. Am. Museum Nat. Hist. 197:1–139, 1990) cladistic analysis; and also are inconsistent with some inferences based on mitochondrial DNA data. The Sod results manifest how, in addition to the information derived from nucleotide sequences, structural features (i.e., the deletion of an intron) can help resolve phylogenetic issues. Correspondence requests to: F. J. Ayala     

Analysis and prediction of the packing of α-helices against a β-sheet in the tertiary structure of globular proteins

The packing of α-helices and β-sheets in six $\text{α}\text{β}$ proteins (e.g. flavodoxin) has been analysed. The results provide the basis for a computer algorithm to predict the tertiary structure of an $\text{α}\text{β}$ protein from its amino acid sequence and actual assignment of secondary structure.The packing of an individual α-helix against a β-sheet generally involves two adjacent ± 4 rows of non-polar residues on the α-helix at the positions i, i + 4, i + 8, i + 1, i + 5, i + 9. The pattern of interacting β-sheet residues results from the twisted nature of the sheet surface and the attendant rotation of the side-chains. At a more detailed level, four of the α-helical residues (i + 1, i + 4, i + 5 and i + 8) form a diamond that surrounds one particular β-sheet residue, generally isoleucine, leucine or valine. In general, the α-helix sits 10 Å above the sheet and lies parallel to the strand direction.The prediction follows a combinational approach. First, a list of possible β-sheet structures (10⁶ to 10¹⁴) is constructed by the generation of all β-sheet topologies and β-strand alignments. This list is reduced by constraints on topology and the location of non-polar residues to mediate the sheet/helix packing, and then rank-ordered on the extent of hydrogen bonding. This algorithm was uniformly applied to 16 $\text{α}\text{β}$ domains in 13 proteins. For every structure, one member of the reduced list was close to the crystal structure; the root-mean-square deviation between equivalenced C^α atoms averaged 5.6 Å for 100 residues. For the $\text{α}\text{β}$ proteins with pure parallel β-sheets, the total number of structures comparable to or better than the native in terms of hydrogen bonds was between 1 and 148. For proteins with mixed β-sheets, the worst case is glyceraldehyde-3-phosphate dehydrogenase, where as many as 3800 structures would have to be sampled. The evolutionary significance of these results as well as the potential use of a combinatorial approach to the protein folding problem are discussed.     

Pharmacogenomics - it''s not just pharmacogenetics

New technologies in both combinatorial chemistry and combinatorial biology promise to unlock new opportunities for drug discovery and lead optimisation. Using such genome-based technologies to measure the dynamic properties of pharmacological systems, pharmacogenomics can now provide an objective measure of a drug's biological efficacy, including its potential adverse effects.     

Cultivation of Macrocystis integrifolia (Laminariales,Phaeophyta) in southeastern Alaskan waters

The artificial culture of Macrocystis integrifolia in southeastern Alaskan waters has been initiated as a first step in a project to augment the existing herring roe-on-kelp fishery in the state. The growing of Macrocystis in Prince William Sound has the potential of considerably enhancing this fishery by eliminating the costly importation of this kelp from southeast Alaska. In an ongoing feasibility study, Macrocystis has been cultured under laboratory conditions through the embryonic sporophyte stage and outplanted in waters near Sitka, Alaska (57° N). Growth of the outplanted kelps has been monitored as a function of the time and depth of the outplanting. Preliminary results suggest that light is limiting for growth in winter and that the optimal depth for outplanting will vary with the season.     

Synthesis of furanone-based natural product analogues with quorum sensing antagonist activity

The synthesis of 5- and 3-(1'-hydroxyalkyl)-substituted 5H-furan-2-ones 4a-d and 8a-d as well as 5-alkylidene-5H-furan-2-ones 5a-d is described. A study of the structure-activity relationship of these furanone-based natural product analogues towards two different quorum sensing systems is reported. Although the synthesized compounds are not as potent quorum sensing inhibitors as some natural counterparts and a synthetic analogue hereof, interesting structure-activity relationships are seen.     

Thermal inactivation of nonproteolytic Clostridium botulinum type E spores in model fish media and in vacuum-packaged hot-smoked fish products

Thermal inactivation of nonproteolytic Clostridium botulinum type E spores was investigated in rainbow trout and whitefish media at 75 to 93 degrees C. Lysozyme was applied in the recovery of spores, yielding biphasic thermal destruction curves. Approximately 0.1% of the spores were permeable to lysozyme, showing an increased measured heat resistance. Decimal reduction times for the heat-resistant spore fraction in rainbow trout medium were 255, 98, and 4.2 min at 75, 85, and 93 degrees C, respectively, and those in whitefish medium were 55 and 7.1 min at 81 and 90 degrees C, respectively. The z values were 10.4 degrees C in trout medium and 10.1 degrees C in whitefish medium. Commercial hot-smoking processes employed in five Finnish fish-smoking companies provided reduction in the numbers of spores of nonproteolytic C. botulinum of less than 10(3). An inoculated-pack study revealed that a time-temperature combination of 42 min at 85 degrees C (fish surface temperature) with >70% relative humidity (RH) prevented growth from 10(6) spores in vacuum-packaged hot-smoked rainbow trout fillets and whole whitefish stored for 5 weeks at 8 degrees C. In Finland it is recommended that hot-smoked fish be stored at or below 3 degrees C, further extending product safety. However, heating whitefish for 44 min at 85 degrees C with 10% RH resulted in growth and toxicity in 5 weeks at 8 degrees C. Moist heat thus enhanced spore thermal inactivation and is essential to an effective process. The sensory qualities of safely processed and more lightly processed whitefish were similar, while differences between the sensory qualities of safely processed and lightly processed rainbow trout were observed.